This invention relates to a vehicle steering and front-end alignment defect detector and a method of using the device. More particularly, the invention disclosed herein relates to a device and method for quickly determining whether a steering or front-end alignment defect exists in a dirigible vehicle, such as an automobile, while stationary, by obtaining and comparing the values for steering gain when the vehicle's front wheels are rotated and the steering wheel of the vehicle is steered from center position in one direction and then in the opposite direction.
Although there are many devices in the prior art for detecting steering or front-end alignment defects they are customarily either very complex and cumbersome or very specialized and incapable of determining the existence of such defects in general. An example of the former can be found in the disclosure of U.S. Pat. No. 3,238,772, with which device the existence of such defects can be not only discovered to exist, but also structurally located within the vehicle with notable precision. However, because such devices attempt to diagnose the exact nature and location of any such defects found, they are fairly complex and bulky, often having numerous electronic, electro-mechanical, and mechanical components of substantial size.
Examples of the simpler, more specialized devices can be found in U.S. Pat. Nos. 3,889,527 and 3,813,932. Although each of the apparatus disclosed within them have relatively few and simple components, they both have rather limited applications. The device disclosed in the '527 patent is only intended to test for play in the linkage between the dirigible wheels and the steering wheel of a vehicle. The device disclosed in the '932 patent is an even simpler version of the same type of tool.
Hence, it is an object of the present invention to create a relatively uncomplicated device for quickly detecting the existence, not necessarily the exact nature or location, of any type of steering of front-end alignment defect in vehicles having dirigible front wheels. It is also an object of the present invention that the defect defecting device be less bulky or cumbersome than the diagnostic devices that exist in the prior art.
In the prior art, there are many different types of chassis dynamometers and roller brake testers that are widely used in the vehicle testing industry. Such devices often provide at least one roller for rotating the dirigible front wheels of various types of vehicles, including automobiles, during testing. Since such prior art devices are in widespread use, it is also an object of the present invention to develop a vehicle steering and front-end alignment defect detector that can be used in conjunction with certain of the existing chassis and brake testing machinery in the prior art that utilize such rollers.
In addition, it should be noted that the disclosures in the prior art that can be utilized to diagnose the existence or location of a steering or front-end alignment defect have not shown, mentioned, or suggested the detection of such defects by means of the steering gain concept (the ratio of the force exerted by the rotation of the front wheels in urging the vehicle in the direction turned toward by the operator to the force exerted by the operator in turning the steering wheel). It is therefore a further object of the present invention to use the steering gain concept to detect such defects through use of the steering gain concept.
Lastly, it is nowhere suggested in the prior art that such steering gain can be measured by (1) rotating the front wheels of the vehicle while the vehicle remains stationary, (2) determining the force exerted by the operator in turning the steering wheel, and (3) measuring the force exerted by the front sides of the vehicle on a side motion restraining device having a vehicle urging force determining apparatus mounted therein. It is therefore yet another object of the present invention to use the steering gain concept to determine the existence of a steering or front-end alignment defect in vehicles by means of a front wheel roller or rollers, a steering wheel rotating force determining device, and side motion retainers with vehicle force determining apparatus mounted therein. Additional objects and advantages obtained by the present invention will become readily apparent as the following specification proceeds.